1. Field of the Invention
The present invention relates to a container for housing a coil, which is used when transporting a coil such as a metal strip coil or a paper coil
2. Related Art Statement
When transporting for example a steel strip coil manufactured in a steel works from the steel works to a customer, it is necessary to package the coil to prevent flaws or rust from producing on the coil and dust from depositing thereon. When transporting a steel strip coil by sea, in particular, the coil must be doubly packaged with the use of a water-proof paper and a thin steel sheet.
An example of the process in the case where the coils doubly packaged as described above are transported from a steel works in Japan to an overseas customer is described below.
The doubly packaged coils are transported from a steel works to a bonded warehouse near a shipping port, and are piled up into a plurality of piles in the bonded warehouse for storage. When a freight vessel arrives, the coils stored in the bonded warehouse are transferred into a hold of the freight vessel, and are piled up into a plurality of piles in the hold. The freight vessel loaded with the piled coils departs from the shipping port, and reaches a port near a destination. At the port, the coils are unloaded from the freight vessel, and the unloaded coils are transported by means of a special wagon for coils or the like to the destination.
The conventional packaging and transportation of the coils as described above, have the following problems:
(1) The necessity of double packaging of the coil with the use of a water-proof paper and a thin steel sheet requires much labor, time, materials and cost.
(2) Since loading, unloading and transportation of the coils are carried out a plurality of times during transportation of the coils from the steel works to the final destination, flaws may be easily produced on the coils during handling thereof, and rain considerably reduces the stevedoring operation efficiency of the coils.
(3) Stabilization of the coils piled up into a plurality of piles in the bonded warehouse or in the hold of the freight vessel, requires many stoppers corresponding to the coil size, and the coils piled up into a plurality of piles in the hold of the freight vessel must be fixed to each other by means of ropes in a large quantity.
(4) When the freight vessel on the voyage suffers from a stormy weather or a rough sea, the ropes fixing the coils piled up into a plurality of piles in the hold are loosened, and the coils conflict with each other, causing flaws on the coils. When rolling and pitching of the freight vessel are serious, furthermore, the ropes fixing the coils may be broken and the released coils may be scattered about in the hold, resulting in the impossibility of gathering them.
(5) In order to transport the unloaded coils on land, it is necessary to use a special wagon for coils, and to transport them by rail. The quantity of transported coils is therefore limited.
As a container for housing a coil which solves the above-mentioned problems, Japanese Patent Publication No. 2-53,306 dated Nov. 16, 1990 discloses a container for housing a metal strip coil, which comprises:
a lower box made of steel for housing a metal strip coil with the axis thereof directed horizontally and covering a lower half portion thereof, said lower box having an open upper end;
an upper box made of steel inserted into said lower box so as to be vertically movable in said lower box, for covering an upper half portion of said coil, said upper box having an open lower end and an upper end openable and closeable by means of a pair of shutters;
a lift mechanism for vertically moving said upper box; and
a shutter opening-closing mechanism for closing said upper end of said upper box by closing said pair of shutters when said upper box is moved up by means of said lift mechanism, and for opening said upper end of said upper box by opening said pair of shutters when said upper box is moved down by means of said lift mechanism (hereinafter referred to as the "prior art").
FIG. 7 is a partially cutaway schematic front view illustrating an example of the container of the above-mentioned prior art, and FIG. 8 is a partially cutaway schematic side view illustrating the container shown in FIG. 7. As shown in FIGS. 7 and 8, the container of the prior art comprises a lower box 33 made of steel, having an open upper end, for housing a metal strip coil 1 with the axis thereof directed horizontally and covering a lower half portion thereof; an upper box 34 made of steel, inserted into the lower box 33 so as to be vertically movable in the lower box 33, for covering an upper half portion of the coil 1, which has an open lower end and an upper end which is openable and closeable by means of a pair of shutters 35, 35'; a lift mechanism for vertically moving the upper box 34; and a shutter opening-closing mechanism for closing the upper end of the upper box 34 by closing the pair of shutters 35, 35' when the upper box 34 is moved up by means of the lift mechanism, and for opening the upper end of the upper box 34 by opening the pair of shutters 35, 35' when the upper box 34 is moved down by means of the lift mechanism.
The lower box 33 comprises a rectangular bottom wall 36 formed, of channel-shaped steel members for example, into a lattice, four lower side walls 37 made of a steel sheet, an open upper end, and four lower props 38 made of steel, having an L-shaped cross section, each fixed vertically to each of four corners of the bottom wall 36. A plurality of coil supports 39 are provided on the bottom wall 36 for stationarily supporting the coil 1 housed in the lower box 33.
The upper box 34 has a rectangular cross section. The upper box 34 comprises four upper side walls 40 made of a steel sheet, an open lower end, and an upper end openable and closeable by means of the pair of shutters 35, 35'. The upper box 34 is inserted into the lower box 33 so as to be vertically movable along the four lower props 38 of the lower box 33.
The lift mechanism for vertically moving the upper box 34 comprises four cylinders 41, four hollow pistons 42, and an air supply pipe 43. Each of the four cylinders 41 is vertically fixed to each of the four corners of the upper box 34. The lower end of each of the four pistons 42 is fixed to each of the four corners of the bottom wall 36 of the lower box 33. Each of the four pistons 42 has a piston head 45 having a through-hole 44 at the center thereof, and each of the piston heads 45 is slidably and vertically inserted into each of the cylinders 41.
The shutter opening-closing mechanism comprises a pair of guide rails 46, symmetrically provided on the inner surfaces of a set of the two opposing upper side walls 40 of the upper box 34, for symmetrically guiding the pair of shutters 35, 35', a pair of shutter rewinding rollers 47 each provided on each of the both sides of the bottom wall 36 of the lower box 33, for rewinding respectively each of the pair of shutters 35, 35', and four ropes 48, one end of each of which is fixed to each of the both sides of the leading end of each of the pair of shutters 35, 35' and the other end of each of which is fixed to the lower portion of the upper box 34. Each of the four ropes 48 is stretched along each of the pair of guide rails 46, the upper side wall 40 of the upper box 34 and the bottom wall 36 of the lower box 33. In FIG. 7, 49 is a shutter casing for receiving each of the pair of shutter rewinding rollers 47.
According to the container for housing a metal strip coil of the prior art, the coil 1 is housed in the container as described herebelow. As shown by a two-point chain line in FIG. 7, the upper box 34 is moved down into the lower box 33. In this position, a greater part of each of the pair of shutters 35, 35' are rewound on each of the pair of shutter rewinding rollers 47, and thus; the upper end of the upper box 34 is opened. In this state, the coil 1 is housed in the lower box 33 with the axis of the coil 1 directed horizontally, and is stationarily supported by means of the plurality of coil supports 39 provided on the bottom wall 36 of the lower box 33. Then, a compressed air is supplied into each of the four cylinders 41 through the air supply pipe 43, the hollow piston 42 and the through-hole 44 of the piston head 45. As a result, the upper box 34 is moved up to the uppermost position thereof along the four lower props 38 of the lower box 33 under the effect of pressure of the compressed air thus supplied.
As described above, according as the upper box 34 is moved up, the pair of shutters 35, 35' are pulled by the four ropes 48 and are symmetrically veered out from the pair of shutter rewinding rollers 47 along the pair of guide rails 46. The leading ends of the pair of shutters 35, 35' finally come into contact with each other at the center of the pair of guide rails 46. Thus, the upper end of the upper box 34 is closed, and the coil 1 is completely housed in the container.
The container in which the coil 1 is housed as described above is transported by sea and on land to the final destination, where the coil 1 is taken out from the container as described below. Air in the four cylinders 41 is discharged through the through-hole 44 of the piston head 45, the hollow piston 42 and the air supply pipe 43. As a result, the upper box 34 moves down into the lower box 33, under the effect of its own weight, along the four lower props 38 of the lower box 33. According as the upper box 34 moves down, the four ropes 48 are loosened, and as a result, the pair of shutters 35, 35' having closed the upper end of the upper box 34 are rewound by means of the pair of shutter rewinding rollers 47. Thus, the upper box 34 moves down into the lower box 33, and the upper end of the upper box 34 is opened. The coil 1 can therefore be easily taken out from the lower box 33 with the use of a crane or the like.
According to the prior art described above, favorable effects are available. More specifically, it is possible to simplify the packaging of the coil 1, to prevent the production of flaws on the coil 1 during the handling and the transportation thereof, to conduct the handling of the coil even in rain, to transport the coil on land without using a special wagon for coils, and thus to improve the transporting efficiency of the coil.
However, the above-mentioned prior art has the following problems:
(1) The lift mechanism for vertically moving the upper box 34 inserted into the lower box 33 and the shutter opening-closing mechanism for opening and closing the upper end of the upper box 34 have very complicated structures. Troubles tend therefore to occur in the lift mechanism and the shutter opening-closing mechanism, and the manufacturing cost of the container increases.
(2) Even when the upper end of the upper box 34 is closed by moving up the upper box 34 and closing the pair of shutters 35, 35', gaps exist between the lower box 33 and the upper box 34 inserted into the lower box 33, and between the pair of shutters 35, 35' closing the upper end of the upper box 34 and the four upper side walls 40 of the upper box 34. Rain water, for example, penetrates into the container through the above-mentioned gaps, and this may cause the production of rust on the coil 1 housed in the container.
Under such circumstances, there is a strong demand for the development of a container for housing a coil, which permits the simplification of packaging of the coil, the prevention of production of flaws on the coil during the handling and the transportation thereof, the handling of the coil even in rain, the transportation of the coil on land without using a special wagon for coils, the improvement of the transporting efficiency of the coil, the manufacture of the container at a low cost with a simple structure free from trouble, and the prevention of production of rust on the coil through the prevention of rain water or sea water from penetrating into the container, but a container having such properties has not as yet been proposed.